Incorporation of coenzyme Q10-loaded nanoemulsions in soy protein gels and assessment of the effects in their microstructure and bioaccessibility of the bioactive

Abstract

Coenzyme Q10 (CoQ10) is a potent antioxidant that provides multiple health benefits, but its incorporation into foods is challenging due to its high hydrophobicity. This study aimed to develop soy protein isolate (SPI) gels filled with CoQ10-loaded nanoemulsion. Minimum gelation concentration tests were performed at pH 5, 6 and 7, as well as 11, 13 and 15 (SPI% w/w), to determine the best conditions for gel production. Gels with 15% SPI at pH 7 and various aqueous phase replacements by YNano Q10 (25%–85%) were produced. Uniaxial compression tests indicated that oil droplets were active particles interacting with the microgels of SPI, which structured the protein network. According to the confocal laser scanning microscopy (CLSM) micrographs, the gel structure was formed by microgels, common for SPI gels, and nanodroplets occupied the gels’ pores, possibly interacting with each other and with the protein matrix, forming a type of “emulsion network”; the scanning electron microscopy data corroborated the CLSM results. The stability of CoQ10 was evaluated using instrumental colorimetry and showed that the bioactive was highly stable after 45 days of storage according to instrumental color measurements. Regarding the release of CoQ10 during in vitro static digestion, the bioactive was present in the final digesta of gastric phase (GP) and intestinal phase (IP), indicating that EFGs protected the active against the harsh conditions of the gastrointestinal tract. Notably, the higher the amount of nanoemulsion, the higher the concentration of CoQ10 present in the digesta, and the presence of nanoemulsion droplets did not influence on protein hydrolysis.